1. Field of the Invention
The present invention is in the field of improved automated apparatus for the manufacture of environmental seed cells wherein the entirety of the steps necessary for the fabrication of such cells, namely, selection of individual seeds from a bulk supply, loading of individual seeds into the compression mold cavities of a tableting apparatus and filling of the mold cavities with appropriate types and quantities of protective-environmental material, are effected with a minimum of supervision.
2. The Prior Art
The present invention is directed particularly to an apparatus constituting an improvement of the apparatus disclosed in U.S. Pat. No. 3,640,428.
As conducive to an understanding of the present invention, it should be noted that in order to secure optimum yield per acre of plants grown from seed and especially certain difficultly handled seeds, by way of example, lettuce, there is an increasing trend toward the employment of environmental seed cells comprising a single seed disposed within a protective mass of encapsulating material which also facilitates germination and growth of the seedling. The utilization of environmental seed cells produces further economies by enabling the seeds to be planted at ideal spacings or intervals, eliminating the necessity for time consuming thinning operations.
In contrast to the larger and, hence, readily handled seed cells, individual seeds, e.g. lettuce, cannot be planted in precisely spaced relation, necessitating under-planting, with consequent waste of space, or over-planting and subsequent thinning.
The advantages of environmental seed cells having been fully outlined in U.S. Pat. No. 3,690,034, they need not be further discussed herein.
The fabrication of such cells, however, and particularly the fabrication in an efficient and highly automated manner, present unique difficulties. By way of example, it is highly desirable that each environmental cell contain one, and only one, seed, or else optimum spacing cannot be achieved. Further, the seeds typically employed are extremely small, increasing the difficulty of automatically selecting a single seed from a bulk mass and depositing the single seed in the cell forming equipment.
A further difficulty inhering in the fabrication of environmental seed cells lies in the fact that many of the preferred materials employed as blanketing or protective layers for the seed (see U.S. Pat. No. 3,690,034) are extremely difficult to handle, measure, feed and process. For instance, a preferred form of environmental seed cell will include outer layers comprised largely of vermiculite and inner layers or blankets comprised of a material having extremely small particle size, such as finely ground "Sorbitol." As is well known, vermiculite is an extremely low density material having a relatively large particle size per unit density, whereby feeding of the material in precise quantities is a difficult undertaking. Similarly, Sorbitol, when milled to small particle size, is a fluffy material, subject to scattering when exposed to turbulent conditions, etc.
While the art of forming tablets from pulverulent material is a well developed one, the tableting of such materials as are preferably employed in the formation of environmental seed cells will be seen to present unique problems. Similarly, the selection from a bulk supply, transferring and positioning of articles as small and light as seed, by automated means, present special difficulties.